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ADO.NET interview questions: - How to add/remove row is in “Data Table” object of “Dataset”? How to load multiple tables in a Dataset & adding relation between tables in a Dataset?
“Data table” provides “NewRow” method to add new row to “Data Table”. “Data Table” has “DataRowCollection” object that has all rows in a “Data Table” object. Following are the methods provided by “DataRowCollection” object: -
Add
Adds a new row in Data Table
Remove
It removes a “Data Row” object from “Data Table”
Remove At
It removes a “Data Row” object from “Data Table” depending on index position of the “Data Table”.
Load multiple tables in a Dataset: -objCommand.CommandText =
"Table1" objDataAdapter.Fill(objDataSet,
"Table1") objCommand.CommandText =
"Table2" objDataAdapter.Fill(objDataSet,
"Table2")
Above is a sample code, which shows how to load multiple “Data Table” objects in one “Dataset” object. Sample code shows two tables “Table1” and “Table2” in object ObjDataSet.
lstdata.DataSource =
objDataSet.Tables("Table1").DefaultView
In order to refer “Table1” Data Table, use Tables collection of Datasets and the Default view object will give you the necessary output.
Adding relation between tables in a Dataset: -Dim objRelation As
DataRelation objRelation=New DataRelation("CustomerAddresses",objDataSet.Tables("Customer").Columns("Custid") ,objDataSet.Tables("Addresses").Columns("Custid_fk")) objDataSet.Relations.Add(objRelation)
Relations can be added between “Data Table” objects using the “Data Relation” object. Above sample, code is trying to build a relationship between “Customer” and “Addresses” “Data table” using “Customer Addresses” “Data Relation” object.
See the following ADO.NET
interview questions video on dataset is a disconnect while datareader is
connected: -
http://
http://questpond.com/
Contributed by:
Shivprasad koirala Koirala
I am a Microsoft MVP for ASP/ASP.NET and currently a CEO of a small
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